DSpace Collection:https://dspace.lboro.ac.uk/2134/9783
Sun, 02 Aug 2015 20:24:30 GMT2015-08-02T20:24:30ZDevelopment of a numerical model to predict wear in grouted connections for offshore wind turbine generatorshttps://dspace.lboro.ac.uk/2134/17140
Title: Development of a numerical model to predict wear in grouted connections for offshore wind turbine generators
Authors: Dallyn, Paul; Palmeri, Alessandro; El-Hamalawi, Ashraf; Knight, Bob
Abstract: In order to better understand the long term
implications of the grout wear failure mode in large-diameter plainsided
grouted connections, a numerical model has been developed
and calibrated that can take advantage of existing operational plant
data to predict the wear accumulation for the actual load conditions
experienced over a given period, thus limiting the requirement for
expensive monitoring systems. This model has been derived and
calibrated based on site structural condition monitoring (SCM) data
and supervisory control and data acquisition systems (SCADA) data
for two operational wind turbine generator substructures afflicted
with this challenge, along with experimentally derived wear rates.
Description: Presented at ICMSE 2015 : 17th International Conference on Materials and Structural Engineering, Kuala Lumpur, February 12 - 13, 2015 and subsequently published by WASET. World Academy of Science, Engineering and Technology applies the Creative Commons Attribution (CC BY) license to works we publish. This license was developed to facilitate open access – namely, free immediate access to, and unrestricted reuse of, original works of all types. Under this license, authors agree to make articles legally available for reuse, without permission or fees, for virtually any purpose. Anyone may copy, distribute, or reuse these articles, as long as the author and original source are properly cited.Thu, 01 Jan 2015 00:00:00 GMThttps://dspace.lboro.ac.uk/2134/171402015-01-01T00:00:00ZWear in large diameter grouted connections for offshore wind energy convertershttps://dspace.lboro.ac.uk/2134/16301
Title: Wear in large diameter grouted connections for offshore wind energy converters
Authors: Dallyn, Paul; El-Hamalawi, Ashraf; Palmeri, Alessandro
Abstract: The paper provides a critical appraisal of the events surrounding the unexpected settlement of large-diameter monopile foundations for offshore wind energy converters, and will detail experimentation that is to be undertaken to determine the extent of the wear failure mode in such structures. The potential for wear deterioration at the grout-steel interface has been caused by the lack of axial load transfer of the grout and steel and so relative movement between the grout and steel is occurring. Hence, a better understanding of this phenomenon is of key importance to determine the long term integrity of the structure. The remedial solution currently favoured within industry consists of the installation of elastomeric bearings, which however may further exasperate the wear due to its lower stiffness than steel contact currently occurring, also because of the presence of water in the grouted connection. The aim of the testing is therefore to identify the risk to offshore foundation integrity due to grout wear under conditions typically observed during life-time operation of offshore wind turbines. The main factors influencing the wear rate of grout will be identified, and the possibility to define indicators for the integrity of the grout that could be used for offshore inspection will be also considered.
Description: Closed access. This is a conference paper.Sun, 01 Jan 2012 00:00:00 GMThttps://dspace.lboro.ac.uk/2134/163012012-01-01T00:00:00ZCost-effective parabolic trough foundations for concentrated solar power plantshttps://dspace.lboro.ac.uk/2134/16299
Title: Cost-effective parabolic trough foundations for concentrated solar power plants
Authors: Dallyn, Paul; El-Hamalawi, Ashraf; Palmeri, Alessandro
Abstract: As part of the continuing requirement for a broad sustainable energy mix, substantial investment is being currently made into renewable energy, including concentrated solar power (CSP). To improve the financial viability of this under-developed technology, research into optimising design is underway in order to reduce the large capital costs associated with CSP plants. At present around 30 % of capital costs of a 50 MW farm are in the solar field (Vallentine et al., 2009), due to the large number of solar collector assemblies (SCAs) required, and therefore there is a large potential to reduce the overall cost by optimising the design of the SCAs and their foundations.
The challenge arises in reducing material and weight, and in simplifying manufacture and assembly, while maintaining the structural rigidity, as the efficiency of the collectors is highly dependent on the optical accuracy. This can be potentially compromised by the wind loading, which is predicted to be the most significant source of optical error (Kolb and Diver, 2008), particularly for flexible systems. A literature review has highlighted that considerable effort has been put into optimising SCA design, but the foundations have been neglected. As well as this there is limited understanding of the loads experienced by the foundations of SCAs.
This paper will present the current level of understanding of SCA loading and how this knowledge can be used to derive the variation in foundation design across the solar field and therefore allow optimisation of foundation design, highlighting potential capital savings that can be made in a typical 50 MW CSP plant.
Description: This is a conference paper.Sun, 01 Jan 2012 00:00:00 GMThttps://dspace.lboro.ac.uk/2134/162992012-01-01T00:00:00ZMonitoring the passivity of steel subject to galvanic protectionhttps://dspace.lboro.ac.uk/2134/13589
Title: Monitoring the passivity of steel subject to galvanic protection
Authors: Holmes, S.P.; Christodoulou, Christian; Glass, Gareth K.
Abstract: This work investigates the assessment of the passivity of steel in concrete subject to galvanic protection. Under atmospherically exposed conditions the kinetics of the cathodic reaction often exhibit activation controlled behaviour. It is shown that in these conditions the corrosion rates estimated from a large negative potential shift are very similar to those determined using the more widely accepted polarisation resistance method. The results are considered in the light of the potential decay cathodic protection criterion, and show how criteria based on potential shift may be improved to monitor steel passivity induced in a galvanic cathodic protection system. This provides the basis for an improved reinforced concrete acceptance criterion that is focussed on the condition of the structure and is included within the ISO standard cathodic protection when applied to galvanic systems.
Description: This is a conference paper.Tue, 01 Jan 2013 00:00:00 GMThttps://dspace.lboro.ac.uk/2134/135892013-01-01T00:00:00Z